legacycentral bbs

Hey guys, I think this weekend I will go ahead and replace my intake manifold gaskets. It appears to be a issue since when I use revscan to check my fuel trims from 4-7 the trims are as high at 14.8 which is the limits I am pretty sure. Which also explains shitty fuel economy and crappy power, I have swapped o2 sensors, cleaned the maf, swapped over the throttle body, fuel pump, injectors, same thing!

Anyone else found the intake manifold gaskets to be broken?

Swapped an EJ22 that always seemed down on power and mileage from my friends '97 Brighton to a '96 Outback that had a blown EJ25.

During the course of the swap I pulled the intake manifold off and found one of the manifold gaskets was folded over on itself causing a major vacuum leak. Replacing that made the EJ22 run like it should have in the first place. I could see how your problems might be related to an intake manifold leak.

this weekend im going to do them in that case

Worst case it can't hurt and you'll know for sure that they're good!

thats what i was thinking.

Well replaced them, old ones seemed fine maybe slightly leaked? Seems quieter now maybe.

Boosts up to 8.9psi no problems, just doesn't have alot of power, even like first gear, just seems sluggish hmm. I am no very happy still. My fuel trims keep wanting to go positive, and my IAC duty cycle is showing 25%.

I am using revscan btw, no knocking, 100% OF.

How can a exhaust restriction affect things? I am running my 3" non catted DP into the stock mid and I wonder how the mid pipe cat is? Thinking about knocking it out and seeing how the car drives.

IAC Idle Air Controller just regulates idle speed.

Midpipe cat could cause your problems as well I suppose, a severely plugged cat makes a car feel really sluggish in my experience. Even worse at higher RPM. Never had a Subaru with an older cat so I couldn't tell ya how that feels, but it can't be too much different. I'm not really leaning towards this because I don't believe a bad cat would make your fuel trims go full positive.

Logically, I'd suspect a leak in your intake tract after the MAF and most likely after the turbo as well. With all mechanical suspects taken care of (injectors, MAF, fuel pump, and TB) the most likely thing is an intake tract leak. It could explain your lack of power in boost easily as well as poor fuel mileage.

Did it just recently lose all this power or has it been this way since you got the car? My SS is kind of slow and sluggish at 9ish psi and gets 23-25mpg if I cruise easy with 90/10 highway/city. Same mileage but way more kick with it turned up to 13ish.